Correction of static pressure on a research aircraft in accelerated flight using differential pressure measurements

Rodi, Alfred R.; Leon, D.

doi:10.5194/amt-5-2569-2012

Cited by 28 publications

(19 citation statements)

References 15 publications

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“…Boegel and Baumann, 1991;Lenschow and SpyersDuran, 1989;Tjernstroem and Friehe, 1991;Khelif et al, 1999). Rodi and Leon (2012) describe a method to directly calculate the flow angles, dynamic pressure and static pressure error solving a set of equations that follows from the (two-dimensional) which is used to calculate the wind from an aircraft. (b) Expanded wind triangle; the figure includes the sideslip angle β.…”

Section: Introductionmentioning

confidence: 99%

Calibration of 3-D wind measurements on a single-engine research aircraft

2015

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Abstract. An innovative calibration method for the wind speed measurement using a boom-mounted Rosemount model 858 AJ air velocity probe is introduced. The method is demonstrated for a sensor system installed on a mediumsize research aircraft which is used for measurements in the atmospheric boundary layer. The method encounters a series of coordinated flight manoeuvres to directly estimate the aerodynamic influences on the probe and to calculate the measurement uncertainties. The introduction of a differential Global Positioning System (DGPS) combined with a highaccuracy inertial reference system (IRS) has brought major advances to airborne measurement techniques. The exact determination of geometrical height allows the use of the pressure signal as an independent parameter. Furthermore, the exact height information and the stepwise calibration process lead to maximum accuracy. The results show a measurement uncertainty for the aerodynamic influence of the dynamic and static pressures of 0.1 hPa. The applied parametrisation does not require any height dependencies or time shifts. After extensive flight tests a correction for the flow angles (attack and sideslip angles) was found, which is necessary for a successful wind calculation. A new method is demonstrated to correct for the aerodynamic influence on the sideslip angle. For the three-dimensional (3-D) wind vector (with 100 Hz resolution) a novel error propagation scheme is tested, which determines the measurement uncertainties to be 0.3 m s −1 for the horizontal and 0.2 m s −1 for the vertical wind components.

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Section: Introductionmentioning

confidence: 99%

Calibration of 3-D wind measurements on a single-engine research aircraft

2015

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“…The probe's shape has been thoroughly testet in wind tunnels e.g. (De Leo and Hagen , 1976) (Mühlbauer , 1985) and analysed theoretically (Rodi and Leon , 2012) to be expressed by a linear proportionality: further details and a full list of all flight legs is given in Kohnert et al (2014). l the averaged length, vg the averaged ground speed, ∆t is the time difference between both legs, ∆χ the difference in the track angle, ∆|U | the difference in the wind speed, ∆u and ∆v the differences of the horizontal wind components (u positive to the East and v positive to the North), ∆u ⊥ and ∆v the differences in components of the wind rotated to align with the track angle, and βr the remaining offset in the β-angle (10).…”

Section: Angle Of Attack Alphamentioning

confidence: 99%

The Polar 5 airborne measurement of turbulence and methane fluxes during the AirMeth campaigns

Hartmann

Gehrmann

Sachs

et al. 2018

Preprint

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Abstract.Low level flights over tundra wetlands in Alaska and Canada have been conducted during the AirMeth campaigns to measure turbulent methane fluxes into the atmosphere. In this paper we describe the instrumentation and new calibration procedures for the essential pressure parameters required for turbulence sensing by an aircraft that exploit suitable regular measurement flight legs without the need for dedicated calibration patterns. We estimate the accuracy of the mean wind and the turbulence 5 measurements. We show that airborne measurements of turbulent fluxes of methane and carbon dioxide using cavity ring down spectroscopy trace gas analysers together with established turbulence equipment achieves a relative accuracy similar to that of measurements of sensible heat flux if applied during low level flights over natural area sources. The inertial subrange of the trace gas fluctuations cannot be resolved due to insufficient high frequency precision of the analyser but since this scatter is uncorrelated with the vertical wind velocity, the covariance and thus the flux is reproduced correctly. In the covariance

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“…Data collected by the University of Wyoming King Air research aircraft (UWKA) form the primary observational basis of this study. Aside from airborne measurements of the basic state variables of wind and temperature, key measurements include accurate static pressure (Rodi and Leon 2012) and precise aircraft altitude based on differential GPS (Parish and Leon 2013). Such measurements allow the horizontal pressure gradient force to be evaluated and hence the ageostrophic nature of the wind field can be explored.…”

Section: A Overviewmentioning

confidence: 99%

Aircraft Measurements and Numerical Simulations of an Expansion Fan off the California Coast

Parish

Rahn

Leon

2016

Journal of Applied Meteorology and Climatology

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Mountains along the California coastline play a critical role in the dynamics of marine atmospheric boundary layer (MBL) airflow in the vicinity of the shoreline. Large changes in the MBL topology have been known to occur downwind of points and capes along the western coast of the United States. Large spatial gradients in wind and temperature become established that can cause anomalous electromagnetic wave propagation. Detailed airborne measurements using the University of Wyoming King Air were conducted to study the adjustment of the MBL to the Point Arguello and Point Conception headlands. Pronounced thinning of the MBL consistent with an expansion fan occurred to the south of Point Conception on 13 June 2012. A sharp cloud edge was collocated with the near collapse of the MBL. D-value cross sections derived from differential GPS altitude measurements allow assessment of the vertical profile of the horizontal pressure gradient force and hence thermal wind forcing in response to the near collapse of the MBL. The Weather Research and Forecasting Model was run with a 1-km grid spacing to examine the atmospheric adjustment around Point Conception during this period. Results from the simulations including the vertical cross sections of the horizontal pressure gradient force were consistent with the aircraft observations. Model results suggest that divergence occurs as the flow rounds Point Conception, characteristic of an expansion fan. Wind speeds in the MBL increase coincident with the decrease in MBL thickness, and subsiding flow associated with the near collapse of the MBL is responsible for the sharp cloud edge.

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Correction of static pressure on a research aircraft in accelerated flight using differential pressure measurements

Cited by 28 publications

References 15 publications

Calibration of 3-D wind measurements on a single-engine research aircraft

Calibration of 3-D wind measurements on a single-engine research aircraft

The Polar 5 airborne measurement of turbulence and methane fluxes during the AirMeth campaigns

Aircraft Measurements and Numerical Simulations of an Expansion Fan off the California Coast

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